Typical consumer detergent compositions may have pH values ranging from 7 to as high as 11. However, low pH detergent compositions, e.g., compositions having a pH ranging from about 2 to about 6, can provide a variety of benefits. Low pH compositions may reduce malodor on fabrics, aid in the release of calcium soaps that tend to capture soils on fabrics, improve performance on pH-sensitive stains, and even provide benefits on fabric feel.
Low pH approaches have been avoided, particularly in enzyme-containing liquid detergent formulations, because low pH may cause enzyme instability (and hence, reduced enzyme activity) in a liquid detergent composition. A low pH may lead to the denaturation of enzymes, resulting in a loss of enzymatic activity. Furthermore, in some low pH detergent compositions, low pH is achieved by the use of citric acid, a weak acid that is also used as a builder. Citric acid has been found to lower enzyme activity in liquid detergent compositions.
Therefore, there remains an ongoing need for a low pH liquid cleaning composition that is compatible with enzymes.